A hot-melt adhesive is a solvent-free adhesive and has a characteristic that instant bonding and high-speed bonding can be achieved since adhesiveness is exhibited after the adhesive is melted by heating and applied onto an adherend, followed by cooling to solidify the adhesive, and therefore has been used in a wide range of fields. Not only adherends to be bonded with such a hot-melt adhesive but also the conditions of use thereof are various. At present, various hot-melt adhesives for use in various applications have been developed and supplied to the market. Also for the conditions of use, various operating temperatures ranging from low temperatures to high temperatures are taken into consideration.
A propylene-based polymer has heretofore been used as a base polymer for hot-melt adhesives. Above all, a low-molecular-weight polypropylene produced through polymerization using a metallocene catalyst has a high flowability and is excellent in coatability when used as a hot-melt adhesive, excellent in adhesion strength with a low-polar substance such as polypropylene or the like and excellent in thermal stability in a molten state under heat, and can be therefore favorably used as a base polymer for various hot-melt adhesives (PTL 1). In particular, the polymer is suitable for spray coating for use in constructing hygiene products such as paper diapers, sanitary goods, etc.